Field of the Invention
The invention relates to a device for extemporaneously or improvisationally raising a transport roller in a feeder of a sheet processing machine and, more particularly, such a transport roller which is swivelably arranged on a shaft supported crosswise, i.e., transversely, in a frame of the machine above a feed table, so as to execute stroking or reciprocating movements in synchronism with the machine and be liftable from the feed table extemporaneously by a swiveling motion of the shaft. The term "transport roller" encompasses those rollers which are operative for sheet transport in the feeder, especially the synchronizing rollers in the feeder of sheet-fed printing presses.
A device having these generic features has become known heretofore from published Japanese Patent Document JP-Sho 63-52841 describing a synchronizing roller in a feeder of a sheet-fed printing press. The synchronizing roller is disposed at the end of a lever which is firmly seated on a shaft which swings or oscillates over a rotary angle range, by means of a cam drive, in synchronism with the printing press, so that the synchronizing roller, or a plurality of synchronizing rollers disposed side by side periodically lift up so as to insert the respective next sheet in succession by the leading edge thereof between transport means, such as conveyor belts or tapes, for example, of the feed table and the synchronizing rollers. Thereafter, the synchronizing rollers descend again and press the sheet against the aforementioned transport means. Side-by-side synchronizing rollers are all disposed on the same shaft. For the purpose of facilitating the removal of a sheet from a feeder, for example in a press arrangement for a printing job or if there is a problem during operation, the synchronizing rollers in this conventional arrangement can be raised from the sheet on the feed table, in a condition wherein the printing press is at rest, by swiveling a hand lever. To that end, the hand lever is secured to an eccentric cam, which is rotatably supported in the frame of the printing press and is operative when pivoted counter to a lever arm secured to the shaft of the synchronizing rollers.